toyvette81

the car used to run great and had good throttle response but within the last year the check engine light has came on here and there , a new oxygen sensor fixed that for about 6 months , at cold start up the car will idol high( like it is suposed to) then drop down when its warm, now the car will drop down again and idol too low ( causes the car to shutter) and this trips the check engine light?? the car will also not take the gas at full acceleration( so it dosent respond liek it used to and dosent take gas all the way through.. but eventualy catches up after it has started choking out) adjusting the idol lasts for about 1 trip around the block im leaning to a carb rebuild has any one had this problem?? input?

Bangkok Dean

ttt

terry82

i would check the cat .they plug up .what do the plugs look like ?

Dalannex

Is the car bone stock, including all emissions and ECM equipment? Could you check the ECM codes and post what you come up with? Take the top off of the carb and while it is running warm nail the throttle and watch the secondaries to see what they do. They could be falling open due to a broken spring. (Although I doubt it) We need to know what code is set in the computer first off though, then we'll talk about further diagnosis.


-Justin

tersian

When the 81 starts, the computer goes automagically to full rich, as the O2 sensor warms and the coolant temp sensor starts to report. This is called open loop. Once everything warms up, and some time has passed the ECM starts to pay attention to the data it gets from the O2 sensor and a coolant sensor. It then starts to modify the signal to the M/C solenoid(mixture control solenoid). This is when the system goes into a closed loop.

If you suspect your O2 sensor, you should check the voltage at idle, and then as it warms. When the mixture is rich, a high voltage signal is sent to the computer(up to 1 volt) and when it is lean, it could be as low as .2 volts. This is what commands the ECM to activate the M/C solenoid.

Hope this helps a little.

-B

platato

I think the O2 sensor MUST be at least 600 degrees F when checked and will often cool down too much if left at an idle for awhile. I'm showing lean = below 450mv rich = above 450mv

What code are you throwing?

Platato

81 4spd Scooter

I just recently experienced this same prob...(slow on accelarator response and engine light on). I had to have my carb re-built (mainly the linkages and gasket replacements) Kept original carb...works great now and feel improvement in accelaration. Good luck

bn7035

My 81 was doing about the same as you describe. After reading the shop manual, studying the codes and trouble shooting quide, I finally figured out the computer was bad. I got a computer on ebay for $15. It even had a better chip in it. Runs great now......... well after I get the fuel tank back in it. At first I did not like the computer but now that I have a basic understanding of it, the computer will help you figure out what needs to be fixed and what is working properly.

Amanda1985

My car has been fine then all of the sudden it acts as if it's on neutral and wont accelerate. I have to power off the car then begins to work fine. The codes say something about a solenoid being stuck. And an 02 sensor. Help I thought it was a bad transmission control module but I replaced it. I'm still having problems.